1993 WR500R Waverunner

[swstanton]

Hi, I'm new to the jetski world so be kind. I got a really good deal on a couple of jetskis and dual trailer. The second one is the 1993 WaverRunner with the single carb 500 motor. One cyl 75psi the other 75 psi not so good but it does start and run. I haven't had it in the water so I have know idea how the performance is. I have a few questions that maybe somebody can help with.

Can I replace the 500 with a 650 that are in the VXR-650?

If so will I need to change the carb and exhaust?

Does the 650 have an oil pump and if so will I'll need all that to do the swap?

Are there any performance parts for either the 500 or the 650 or what can I do to give it a little more power.

Thanks

[harveynailbanger]

Re: 1993 WR500R Waverunner

if the 500 runs with low compression your best bet would seem to me to rebuild top end and maybe new reeds? as for oil easy way to fix that is throw the pump as far as you can and run premix sbt sells block off kits for like 15.00 or something. very simple and it lightens up the ski(small performance gain) honestly dont know if motors will swap but pretty sure they dont use same pump. so any performance gain really isnt worth it. i was just given a 91 vxr 650 and general consensus is why hot rod a VW when u want a porsche. its not a fast ski no matter what you do . it is how ever an economical ski to run and pretty simple to learn on:emoticonw
god luck and let us know how it goes,
Rick

[wmsky]

Re: 1993 WR500R Waverunner

I have an 89 WR500F Waverunner. I believe that factory compression is 140. I suspect that your compression gauge may be wrong. I actually didn't think that the motor would run with only 75 psi. Drop a teaspoon of oil into the spark plug hole and recheck the compression. If it goes up more than 15 psi or so, your rings are probably bad.

There's not much you can do to increase the performance of the motor. About all you can do for the motor is to install an aftermarket f/a (flame arrestor), some Boyesen Power Reeds, a primer kit, and if you can find it, a Mikuni 38mm SBN carb instead of the 38mm BN carb that's already on there. The carbs are the same size, but the SBN has replaceable jets, which will let you take advantage of the small increase in air flow that the other mods will give you. But to tell you the truth, you might not even notice the small increase the mods will give you once you're in the water.

I would expect you'd get a better boost in performance by replacing the impeller, replacing the intake grate or modifying it my cutting out a bar or two, and replacing the ride plate.

Don't get me wrong. The WR500 is a fun ski. With it's flat bottom, it slides out in turns easier, and that can be a lot of fun for just horsing around in the water. Just don't expect much in the way of speed. If you get up to 30mph, you're doing good.